HR: 12:05h
AN: AE31B-07    [PDF]
TI: Lightning Initiation Locations as a Remote Sensing Tool of Thunderstorm Electrical Evolution
AU: * Marshall, T C
EM: marshall@olemiss.edu
AF: University of Mississippi, Department of Physics and Astronomy PO Box 1848, University, MS 38677 United States
AU: Coleman, L
EM: leonidas@phy.olemiss.edu
AF: University of Mississippi, Department of Physics and Astronomy PO Box 1848, University, MS 38677 United States
AU: Maggio, C
EM: crmaggio@olemiss.edu
AF: University of Mississippi, Department of Physics and Astronomy PO Box 1848, University, MS 38677 United States
AU: Stolzenburg, M
EM: mstolzen@phy.olemiss.edu
AF: University of Mississippi, Department of Physics and Astronomy PO Box 1848, University, MS 38677 United States
AU: Hamlin, T
EM: thamlin@nmt.edu
AF: New Mexico Institute for Mining and Technology, Geophysical Research Center, Socorro, NM 87801 United States
AU: Krehbiel, P
EM: krehbiel@ibis.nmt.edu
AF: New Mexico Institute for Mining and Technology, Geophysical Research Center, Socorro, NM 87801 United States
AU: Rison, W
EM: rison@ee.nmt.edu
AF: New Mexico Institute for Mining and Technology, Geophysical Research Center, Socorro, NM 87801 United States
AU: Thomas, R
EM: thomas@nmt.edu
AF: New Mexico Institute for Mining and Technology, Geophysical Research Center, Socorro, NM 87801 United States
AB: The New Mexico Tech Lightning Mapping Array (LMA) uses time of arrival to locate impulsive radiation sources in individual lightning flashes. The close time coincidence between LMA and antenna data [Maggio et al., this conference] suggests that the initial LMA radiation source from a lightning flash is located within about 300 m of the flash's initiation point. Locations of the initial sources should indicate electrically active parts of a cloud and, particularly, regions with strong electric field (SEF). In this study we investigate the electrical evolution of a small thunderstorm in New Mexico that produced 74 lightning flashes. We compare the locations of the 74 initial radiation sources to the evolution of precipitation in the storm cells and to the evolving electrical structure derived from four balloon soundings of electric field (E). A time-altitude plot of the initial lightning sources in this storm reveals four distinct stages. These stages are based on the altitude range of strong electric fields inferred from the initial sources; balloon E soundings confirm these inferences in the first three stages. The early stage shows upward development of the SEF region and was associated with the upward growth of substantial precipitation. In the early-mature stage, the SEF region was between 7.7 and 9.2 km altitude. All the lightning in the first two stages was either intracloud or hybrid cloud-to-ground (CG). In the late-mature stage there were two SEF regions: one between 7.7 and 9.7 km altitude and the other (associated with normal CG flashes) between 4.9 and 6.1 km. In the late stage the SEF region was between 7.0 and 8.0 km altitude and was associated with the dynamical decline of the storm. Preliminary analyses indicate that the initial sources were usually located above and or to the side of the principal reflectivity core in the storm. The initial sources were located in reflectivities of 30-45 dBZ, while the cores had reflectivities of 45-60 dBZ. Implications about possible charging mechanisms will be discussed.
DE: 3304 Atmospheric electricity
DE: 3314 Convective processes
DE: 3324 Lightning
SC: Atmospheric and Space Electricity [AE]
MN: 2003 Fall Meeting